Chronic UV exposure to the eye has been linked to the development of pterygium. However, the pathogenesis of this effect is unclear. We propose that UV may trigger this vascular hyperproliferative lesion by the induction of conjunctival and corneal cytokines and growth factors that result in overgrowth of the conjunctiva into the cornea. Specific Aims: 1: To determine the effect of UV on specific corneal and conjunctival epithelial cell cytokines and growth factors. 2: To examine the production of specific cytokines and growth factors in human pterygium tissue.